Cheapest priced copy (Dark Ascension): $0.59 at Card Kingdom, near mint, their price list as of .
Feed the Pack 
Enchantment · Rare · Dark Ascension · #114
At the beginning of your end step, you may sacrifice a nontoken creature. If you do, create X 2/2 green Wolf creature tokens, where X is the sacrificed creature's toughness.
Legal inCommanderModernLegacyVintage
Not legal inBrawlStandardPioneerPauper
2 printings · $0.59 to $4.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Dark Ascension | 114 | Rare | $0.59 | $4.49Out of stock |
| Jumpstart 2022 | 657 | Rare | $0.69 | — |
2 rulings from Wizards of the Coast
- 22 January 2011You choose whether to sacrifice a nontoken creature and which creature to sacrifice when Feed the Pack’s ability resolves.
- 22 January 2011Check the sacrificed creature’s toughness as it last existed on the battlefield to determine how many Wolves you put onto the battlefield.